I know we have the debate back and forth about SEO vs paid search sometimes, but I thought this was very interesting from Overstock:

"While we work to adapt to Google’s changes, we are increasing our emphasis on other marketing channels, such as sponsored search and display ad marketing, which are generating revenue growth but with higher associated marketing expenses than natural search."

Overstock Blames Change To Google Search Rankings For Hurting Its Growth

I'll be using this when talking about SEO vs Adwords when I have those discussions with clients.